循环载荷处理对非晶合金结构与性能的影响

项目名称： 循环载荷处理对非晶合金结构与性能的影响

项目编号： No.51271095

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 姚可夫

作者单位： 清华大学

项目金额： 80万元

中文摘要： 本项目的目标是认识施加低于屈服强度的循环载荷对非晶合金结构与性能的影响，探索提高非晶合金塑性的新思路。拟采用Ti基、Zr基、Fe基块体非晶合金为研究材料，实验研究循环载荷大小、循环载荷处理周次数对循环载荷处理后非晶合金的结构弛豫、模量、热稳定性和力学性能的影响规律；采用正电子湮灭技术测试分析循环载荷处理前后非晶合金的正电子寿命变化，揭示循环载荷处理对非晶合金正电子寿命谱和对应于不同尺度缺陷的正电子寿命分量的影响规律；建立不同尺度缺陷与非晶合金宏观性能间的关联；认识循环载荷作用对非晶合金结构弛豫、缺陷、宏观性能的影响机制，探讨非晶合金的形变机制；并通过非晶转变温度Tg附近等温退火，揭示退火热处理效应对非晶合金循环载荷处理效应的影响。在实验研究的基础上，提出改善非晶合金塑性的思路和方法。为认识非晶合金形变机制和提高非晶合金塑性提供科学依据和实验基础。研究工作具有重要理论意义和潜在实用价值。

中文关键词： 非晶合金；塑性变形；循环载荷；正电子湮灭；缺陷

英文摘要： In present work, the main goal is to reveal the effects of applied cycling load on the structure and properties of bulk metallic glasses (BMGs, or called bulk amorphous alloys (BAAs)), and explore new ways for enhancing the plasticity of BMGs. In this research, Ti-, Zr- and Fe-based BMGs, which possess difference plasticity, are selected as the model materials for study. Cycling load will be applied to act on the BMG samples using a fatigue testing machine. The influence of cycling load and cycling amount on the structure relaxation, density, elastic modulus, thermal stability and mechanical properties of the studied BMGs will be investigated and made clear. The positron annihilation lifetime (PAL) within the BMG samples before and after applying cycling load will be measured. The variation of PAL spectrum and resolved PAL spectra which corresponding to the defects with different size scale versus the cycling load processing parameters will be revealed. Then, we will try to correlate the defects with different size scale with the property of the BMGs, trying to understand the affecting mechanism of cycling load treatment on structure relaxation, defects and property of BMGs as well as the deforming mechanism of BMGs. Through isothermal annealing of the BMG samples treated by cycling load at the near Tg temperatu

英文关键词： Metallic glass；plastic deformation；cyclic laoding；positron annihilation；defects